Octopuses are taking over the oceans, and no one knows why

A new study published in the journal Current Biologyhas revealed some startling statistics — a group of researchers from the University of Adelaide have found that since the 1950s, the population of cephalopods (octopus, squid, and cuttlefish) in the world’s oceans has exploded. What makes this truly curious is the fact that climate change, overfishing, and ocean acidification have caused the numbers of many fish and shellfish species to plummet during the same period.

Scientists aren’t completely sure what’s causing these tentacled creatures to proliferate so widely, but they have a few theories. One idea is that humans have killed off large numbers of predatory fish that would normally compete with the cephalopods for food. But it’s also possible that these species are simply better equipped to deal with rising ocean temperatures than some other ocean animals.

The lead author of the study, Zoe Doubleday, told Gizmodo that the success of these species can largely be attributed to rapid population turnover rates, saying, “Cephalopods tend to boom and bust—they’re called the weeds of the sea. If environmental conditions are good, they can rapidly exploit those conditions because they grow so fast.”

Unfortunately, this isn’t all good news for the species involved. Researchers warn that if the number of cephalopods rises too high, the animals may be forced to resort to cannibalism due to lack of food. As they take over larger portions of the marine ecosystem, they may also be harvested in greater numbers and become a more important staple in the human diet. Either way, the cephalopod population boom is likely to be a mixed blessing for the species involved.